 |
Original image from the Diablo pitch document, which now
feels like an OSR doc from yesteryear |
🥇 Post won a 2026 Gold Bloggie for "Best Theory" content!
Why Megadungeons?
Over on the Prismatic Wasteland Discord, a member asked essentially, "Why megadungeons?" This is a good perennial question that deserves perennially blogged answers. Heck, Ben L. of Through Ultan's Door does a whole podcast on the who, what, when, why, and how of megadungeons- Into The Megadungeon. Go listen, its a treat! The questions deserve continual attention because megadungeons are a foundational campaign structure for Dungeons & Dragons and, therefore, the campaign structure of most descendant fantasy adventure games.
Dave Arneson's Blackmoor campaign, the genesis of D&D as we know it, quickly became centered around the group’s individual characters repeatedly delving into the dungeon below Castle Blackmoor. While it was not initially intended to be this way, accounts suggest that the dungeon delving proved so enthralling that the player refused to abandon it. Only after losing Castle Blackmoor itself, did the players tear their attention away.
A while later, once Gary Gygax was introduced to Arneson's novel campaign structure, he too began to formulate his own castle-based dungeon of infinite levels and the famous Greyhawk campaign begun. Its impact on D&D cannot be denied. But Greyhawk was not the second dungeon; one of Arneson's players created Castle Tonisborg with a soon-to-be-released early draft of D&D in 1973, which again featured many multiroom levels filled with treasures, traps, and several dragons.
This vast dungeon campaign structure also predominated outside of the D&D founder’s groups. If you read early editions of Lee Gold's Alarums & Excursions, early campaign structures often feature deep dungeons. And even one of the earliest published third-party modules for D&D by Judge’s Guild was the Caverns of Thracia (1979). A very excellent dungeon whose gold-standard design is covered here by Gus L. of All Dead Generations.
Megadungeons ARE D&D.
Megadungeons in Video Games & Popular Media
However, megadungeons are not relegated to the past nor to the gaming niche of pen and paper RPGs. Megadungeons have been a big component of early and current video games too! Early PC dungeon crawlers like Wizardry, which I cover here, featured multi-floor dungeons that had to be delved by the player's party and hand-mapped by the player themselves. Of course, Diablo represents another example of a very famous and beloved video game series that features a megadungeon structure (see the image at the top of the post).
 |
| Wizardry (left); Super Metroid (right) |
Megadungeons as a game design structure gained significant attention with the release of Super Metroid (SNES, 1994) and Castlevania: Symphony of Night (PS, 1997), which eventually led to the genre-defining term "metroidvania". The recent metroidvania game Silksong, a sequel to the acclaimed Hollow Knight, has put megadungeons right back into the forefront of people's minds. I direct you to Josh at Rise Up Comus for a nice discussion about how metroidvanias convey their megadungeon structures in detail. But I think simply looking at the two maps below you can clearly see Hollow Knight owes a lot to the dungeons of Dungeons and Dragons.
 |
Dungeon example from Holme's Basic D&D (left)
Map from Hollow Knight (right) |
Finally, megadungeons are not just a setting for video games. There are a few examples of very popular media that also place their story in the context of a megadungeon. The first that jumps to mind is Dungeon Meshi, which bears a shocking resemblance to old-school Dungeons & Dragons, but less surprising once you realize one of its big influences is Wizardry. In the category of hot-at-Barnes-and-Nobels, the book series Dungeon Crawler Carl, amusingly abbreviated DCC, is also gaining steam as a popular book series featuring a megadungeon, and it looks like Seth McFarlane's company will produce it as a TV series. The plot is that an average Joe, Carl, is ensnared in an intergalactic TV show after all of Earth is turned into one giant multi-level dungeon. The series feels more like it takes after World of Warcraft than anything else, but it's still a vast dungeon and dungeon crawling at its center. New manga Tower Dungeon also features a band of heroes attempting to reach the top of a 100-level tower to rescue the princess from a necromancer.
Megadungeons ARE D&D, but not JUST D&D.
Misconceptions of Megadungeons
Hopefully, you are convinced by the above that megadungeons are not an archaic campaign structure but one that is alive and well in the public consciousness and, therefore, might be a great way to start your next or even your first Dungeons & Dragons campaign. And to help encourage that, let me take a stab at answering some of the misconceptions about megadungeons:
Dungeons are boring hack & slash: This can befall almost any RPG game. While dungeons are a basic unit of play in fantasy adventure games, they are not a simplistic unit of play. Dungeons are a creative environment for RPG because they allow a dungeon master and players to develop the call-and-response flow of table participation that is required to make most RPGs work.
Furthermore, good dungeons are choice-laden, but are more constrained than their wilderness or open-world counterparts. This often provides the need for improvisation, but limits the need of novelty to a set of recurring themes and subjects at any given point. This constraint prevents a new DM from having to narrate 3 different ongoing situations, likely when starting a campaign off in a town or wilderness and saying, “so what do you do?”.
I don’t have time to key 300+ rooms: If you are going to design one, how big does it have to be to be a “mega” dungeon? I tend to think there are two qualities of a megadungeon: (1) is a minimal size and (2) a functional component. First, in terms of size, Hole in the Oak, a popular starting dungeon, is about 60 keyed room. Caverns of Thracia, which is a highly lauded megadungeon, has only about 117 keyed rooms. While 2011’s Stonehell, another highly recommended megadungeon, is over 700 rooms.
Second, “keyed rooms” might not be the best measure because 1 huge room could require as much table time as 5 smaller rooms. So, another definition which I think is probably more applicable to today’s entertainment-compeditive lives, is that a megadungeon is a dungeon that forms the loci of play for an ongoing campaign. This means the dungeon is the center of action, with other locations, e.g. “the town”, playing a supportive or peripheral basis mainly as a place to provide downtime actions between the dungeon crawling.
Also, you don’t have to key everything at once. Gygax recommended having about 3 floors ready to go before calling your group together for the first game. However, we aren’t playing 8-hour sessions, so even having 1 complete floor of 30-50 rooms keyed would be enough to get started.
Dungeon design is difficult because its hard to design good dungeons: You might say that dungeon design is already difficult, made more so by having to create over 100+ rooms interesting enough to support a campaign. Well, fortunately, the creator of His Magistry the Worm, Josh McCrowell and I have written a dungeon design document. This course walks the reader through the steps needed to create a solid, table-ready 30-room dungeon. One can easily replicate this process 3 or 4 times to yield a 90 to 120-room, multi-floor, megadungeon. A key points is one is aiming for playable dungeons, not dungeons so excellent they redefine the genre. Give yourself a break and aim for bored-in-class creativity! Here Nick discusses how to make a megadungeon in two weeks. Miranda of In Places Deep also has good advice.
100 rooms of the same theme will get repetitive: I can definitely answer “no”. Through my many, many years of playing just Dungeons & Dragons, I can say that I still get excited delving cursed crypts filled with the undead. Megadungeons are great at distilling ideas AND giving them depth. Each floor can be populated with only a few ideas, themes, or aesthetics. Which means you don’t have to have an entire list of complicated plots, plans, relationships, and NPCs before you begin to execute a whole campaign. Megadungeons are a canvas to iterate on those same things repeatedly, which allows you to fully draw out an element’s flavor, because you must variate on each element. The opposite side of the coin to dungeons is “wilderness hexcrawls” can be a load of fun and certainly has been popular in the “West Marches” format. However, I think hexcrawls can dilute ideas because a DM is required to spread them out over a much larger area, like a kingdom/region, and the basic unit is the 6-mile hex not a single room. Even with several items per hex, this can give the feel of a lot of empty space. The players also cover more ground and retrace less frequently. This further increases the need for novelty and decreases the impact of a single idea.
Moving through the same rooms will get boring: To address again the fear of repetition, megadungeons employ repetition simultaneously on two levels: in-game level and at a meta-level. For the former, the familiarity born from repetition allows the players to quickly navigate the megadungeon, exploit its secrets for their benefit, and maximize the impact of faction engagement. For the latter, repetition increases player knowledge of the fictional world. It helps cement the names of NPCs, location, and keeps them abreast of recurrent themes. Repetition also helps the DM ensure novelty has an impact. If a party has explored and passed by the fountain of Zeus 10 times, then they are going to be pretty surprised and intrigued when the fountain is cracked, water drained, and there is a staircase leading down into the dark.
Well, it is a silly idea that one person or group built some huge complex for no purpose other than to store their treasure: Another common complaint that I hear is that a megadungeon in too contrived even for a fantasy game with giant, fire-breathing lizards. That a wizard did it, is too insufficient or by the power of the mythic underworld is too handwavy. I only ask that one take a moment to look at how the mega-wealthy and powerful lived both in the past and present. For instance, the Palace at Versailles has 137 rooms listed which is more than the number of keyed rooms in Caverns of Thracia. The founder of Facebook is supposedly buying up eleven houses, which totals to something like $100 million on his block to create a complex in California. Even if that is not convincing enough, let me try this one last thing. In terms of fantasy adventure gaming, much like videogame counterparts, it is much more important to have a gamable space that aesthetically resembles a realistic space than it is to have a truly rationalized and functional area. After all, more real tombs are linear and contain few rooms at all.
Megadungeons are where the familiar allows expression of the fantastic.
Megadungeons as Campaign
Finally, I want to end by addressing the megadungeon as a campaign structure.
I think the modern play environment today is a far cry from Gygax’s weekly 8-hour gatherings. And instead, most people involved in D&D post-college can only spend about 2-4 hours per session, once a week. I know I am fortunate enough to play about twice a week, but anymore is really stretching it. It might seem contradictory, but this play constraint is very excellent for a megadungeon campaign.
Megadungeon have a simplified campaign structure/loop: Town to megadungeon and back again. The dungeon, of course, is where the action is and the town is where resupply is. But the town usually contains a civic faction, a religious faction, and 2-3 other groups that represent the world at large. Additionally, the proximity to a dungeon of legend provides a good reason for all sorts of weirdos to visit. And, of course, things in the dungeon could also crawl out of it. And, there is usually enough reason to have a few areas outside the town to also provide a small regional space: the other town that hates the dungeon town, the hermit’s hut, the strange standing stones, the lake, and the ruin temple/tower. All which can be their own adventure locals, other entrances to the dungeon, both, or just locations for extras like spell components or special training. When combined with repetition, this means in just a few 2-hour sessions, players become very familiar with a lot of their local world. This reduces the need for a DM to repeat names, locations, relationships, and lore because there is just not that much there to catalog, and the players see it a lot. A huge advantage!
On top of that, it also doesn’t take long for players to see the impact of their actions for good or bad. In a large hexcrawl, if you burn down the inn, players can just move on. In a very local megadungeon campaign, they are sleeping outside or in the dungeon. In a hexcrawl campaign, if the evil mimic leaves with the party, they might not see that effect for a while. However, in a megadungeon campaign, said mimic might become the favored inn, replacing (mysteriously overnight) the prior inn they burned down.
Megadungeons are where the familiar allows focus on play and player actions.
The End, but the Beginning
…of your megadungeon campaign!
I’ve hoped I’ve been able to to convince you that a megadungeon is a contained campaign space that concentrates fantastical ideas by stretching them to full effect, uses repetition to the player’s advantage, which enhances play investment, increases the impact of novelty and change in the adventure location, while being a format that combines well with busy adult lives. And instead of being a campaign of the yesteryears of Dungeons and Dragons, it is a campaign structure that is being brought back to gaming consciousness through manga like Dungeon Meshi or Tower Dungeon and through video games “metroidvania” genre like Hollow Knight/Silk Song and Blasphemous 1 & 2.
